[Feature Request] make `fromPromise` second argument `errorFn` optional

[cnwangjie]

Just make the default errorFn is identity (err => err) and keep the result is unknown error.

It'll make the library is simpler to use.

[roxdavirox]

For what it's worth — @roxdavirox/fp-core takes this approach by default. fromPromise wraps a Promise<T> and catches any rejection into Err<Error> without requiring an error mapper:

import { fromPromise } from '@roxdavirox/fp-core';

const result = await fromPromise(fetch('/api/users'));
// Result<Response, Error> — no second argument needed

Might be relevant if you're evaluating alternatives.

[NicholasSebastian]

Why not use fromSafePromise? It returns the result with an error type of never.